Anti-seize Ball and Sleeve Plunger Separator Rod

ABSTRACT

The present invention intends to solve sleeve seizure in ball and plunger lift systems by the use of one or more spherical channel(s) indented into the separating rod. The indented spherical channel(s) act as an air bearing between the separator rod and the sleeve. In addition, the channels direct gas currents in a spherical fashion causing the sleeve to rotate. With this rotation of the sleeve, residues are agitated, as well as sheared off by the edges of the channels. Another benefit of this design is that each time the sleeve is actuated up or down the separator rod, during regular cycles, residues shear off in those actions as well. With the residues continually cleaned off the sleeve during regular cycles, the oil well&#39;s production can continue with depleted formation pressures and may not require injected pressure.

BACKGROUND OF THE INVENTION

Ball and sleeve plungers are widely used in oilfield. These systems are commonly used in gas flowing wells. In gas flowing wells it is essential to move fluid as well as gas to the surface to keep the wells flowing. If a sufficient amount of liquid is not moved out of the well, the resulting column height of the fluid from the bottom of the well builds a pressure too great for the formation pressure to overcome. This created equilibrium is known as “loading up” or the “logging off” of a hydrocarbon well.

The ball and sleeve plunger system, as described in U.S. Pat. No. 8,181,706, solves this problem by bringing certain volumes of liquid to surface as well as allowing a certain volume of gas to escape in a set ratio. The ball and sleeve plunger accomplishes this by using a hollowed sleeve with an outer diameter similar to the inner diameter of the tubing and an inner diameter matching the diameter of a free piston, a simple ball. The lower portion of the sleeve's opening begins larger than or equal to the diameter of the free piston but bevels down to a smaller diameter. The free piston's diameter in substantially less than that of the tubing, meaning that gravity is able to move a free piston (commonly made of steel) beneath the column of fluid. Once the sleeve is released at the top of the tubing, it too moves past the column of fluid and mates with free piston. Formation pressure, greater than the sum of the fluid pressure, local atmospheric pressure and weight of the ball and sleeve, is then applied beneath the sleeve and ball combination and lifts the duo as well as the column of fluid. The fluid exits the orifice at the well head, while the sleeve and ball combination meets a separator rod. The separator rod is concentric with and smaller than the inner diameter of the sleeve. When the sleeve and ball combination is forced into the separator rod, the free piston is dislodged from the sleeve and allowed to fall back down the tubing. The sleeve is held on the separator rod by the drag force of the gas passing by on its way out the wellhead. The sleeve is held at this position for a predetermined time and is then released back down the tubing to complete the cycle. The sleeve is released by equalizing the formation pressure and thus ceasing gas flow.

Problems have arisen for this system in aging wells. When hydrocarbon wells are continually produced the formation pressure, the pressure actuating the production process, starts to deplete. Less formation pressure results in a lower velocity of the sleeve and ball combination when it meets the separating rod. The velocity of the sleeve and ball combination becomes especially important when common well residues accumulate on the inside surface of the sleeve. If the minimum velocity to push the sleeve completely past the tip of and on to the separator rod is not met, a seizing of the sleeve is likely. With the sleeve is seized on the separator rod the cycle is halted. This halt in cycle is a cease of production and an overall loss of revenue.

Adaptations have been made to the separator rod to combat residue accumulation but have failed in creating substantial progress. A possible variable explaining this result is the stagnation of the sleeve experienced while in its position on the separator rod. With the sleeve at rest, residue carried by the gas flowing around the sleeve can jam itself into the tolerances between the sleeve and separating rod. This situation can also cause the seizing of sleeve and interruption of the cycle.

SUMMARY OF THE INVENTION

The present invention seeks to provide a solution to this problem by providing one or more spherical channel(s) recessed into the separating rod. The separating rod typically consists of cylindrical bar stock made of steel or other alloys. The profile of the separating rod includes a cylinder of consistent or fluctuating diameter. The spherical channel(s) act in shearing the accumulation of residues on the inside surface of the sleeve and keeps the sleeve from becoming stagnant in its top position.

The shearing of residue accumulation may be in two sets of shearing actions. The first shearing action would be during any point of the cycle in which the sleeve is passing over the separator rod. This includes the arrival or departure of the sleeve during each cycle. This action is due to the upper and lower edges of the recessed channel(s) being, depending on the spherical angle, somewhat perpendicular to the motion of the sleeve. This attribute results in the edges of the channel(s) acting as a shearing face with the recessed portion acting as clearance for dislodged residue. The dislodged residue is then carried up the channel and out the wellhead. The second shearing action is introduced while the sleeve rotates on the separator rod. While the sleeve rotates (rotation mechanics are discussed below) on the separator rod, any remaining residue on the inner face of the sleeve is sheared off. This attribute occurs due to the edges of the channel(s) being, depending on the spherical angle, somewhat perpendicular to the rotation of the inner face of the sleeve.

The rotation of the sleeve may be due to the dispersion and direction influences of the passing gases over and through the channels. The feature of the channel wrapping around the separation rod may act in dispersing the passing gas on the inside face of the sleeve. This element of the design may cause the sleeve to rest on a cushion of passing air and thereby reducing friction between the inside face of the sleeve and the separator rod. This attribute also may cause the generation of a component of the gas flow direction to be perpendicular to the inner face of the sleeve. Having a perpendicular component of gas current passing over the inner face of the sleeve may create drag and thusly creating a moment about the center of the sleeve. Even with small rotation moments, the rotational motion may be possible due to the low amount of friction opposing it. In addition, rotation of the sleeve reduces the possibility of residues, carried by passing gas currents, from lodging themselves into the tolerances between the sleeve inner face and the separator rod. In addition, if any gas carried residue becomes lodged it would then be subsequently sheared off by the opposing channel edge.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 (Prior art)—depicts an overview of the ball and sleeve plunger system in use on a hydrocarbon well

FIG. 2—depicts an embodiment of the present invention with the intent of describing its purpose

DETAILED DESCRIPTION OF THE INVENTION

For the purpose of this disclosure, the term “plunger” will refer to the combination of the free piston mated with the inner hollow passage of the sleeve. The term “downhole” will refer to the portion of the hydrocarbon well beneath the well head. The term “residue” will refer to residue and debris involved in the drilling, completion and production of hydrocarbon wells (e.g. fracking sands, coalbed residues, paraffin, etc.).

FIG. 2 shows the best mode contemplated by the inventor of the present invention. Shown in FIG. 2 is an example of one embodiment of the present invention with: one set of spherical channels, a linear tip profile, the absence of vertical channels, and a constant structure diameter.

The following description of one embodiment of the present invention is intended to show the value and use of said invention to someone skilled in the pertaining art. The present invention includes but is not limited to the following features disclosed.

FIG. 1 presents an overview of the ball and sleeve plunger as disclosed in the U.S. Pat. No. 8,181,706 in use on a hydrocarbon well. The sleeve 38 is shown separated from the free piston 40. During normal cycles, the free piston is allowed to hit the bottom catch 60 and the sleeve 38 falls during pressure equilibrium and couples with it. The resulting combination of the mate, also known as the plunger, typically forms a seal with the tubing wall 12 capable of holding the formation pressure beneath it. This upward force brings the plunger and fluid to the surface. The produced fluid escapes through the flow line 74 and the plunger is brought into contact with the separator rod 62. The momentum of the plunger created by the upward velocity and the plunger's mass, creates a force typically sufficient to dislodge the free piston 40. Once decoupled, the sleeve's 38 ascent is halted by a stop 70 on the separator rod. The sleeve 38 is held on the separator rod 62 and the stop 70 by the passing gas current escaping through the flow line 74. The duration of the gas flow is predetermined and typically allows the free piston 40 to reach the bottom catch 60 before ceasing and allowing the sleeve 38 to fall back down the tubing 12 and subsequently recoupling with the free piston 40, thus completing the cycle.

FIG. 2 depicts an example of one embodiment of the present invention. The present invention intends to optimize the portion of FIG. 1 (prior art) labeled as 62. During regular ball and sleeve plunger cycles, the design of the separator rod is intends to prevent seizing of the sleeve 38 to the separator rod 62. The separator rod body 1 has a diameter, preferably, equal to or less than the inner face of the sleeve 38. The present invention is depicted with, but not limited to, one set of spherical channels 1 wrapping around the cylindrical body shape of the separator rod body 1. The spherical channels 2 are recessed into the separator rod body 1 at a width that leaves a sufficiently rigid ridge between each channel section. The depth of spherical channel 2 is less than the radius of the separator rod body 1 and typically shallow enough to allow the separator rod body 1 enough rigidity to avoid buckling during plunger impacts. The present invention depicts, but is not limited to a tip profile 4 with linear bevel. The present invention depicts, but is not limited to a separator rod body 1 with a constant diameter. The separator rod body 1 is one solid piece, meaning that parts do not become dislodged and fall downhole. This attribute helps to avoid costly downhole maintenance and long pauses in cycle.

The present invention in this example embodiment has a linear bevel tip profile 4 that may aid in the concentric alignment of the sleeve inner face and penetration of residue accumulation on said surface. Spherical channels 2 on the tip profile 4 may begin the act of shearing residue accumulation, which gives the sleeve 38 clearance to proceed up the separator rod body 1. The tip 5 is the portion that contacts with the free piston 40 during decoupling of the plunger. The tip 5 has a diameter, preferably, small enough to effectively penetrate residue accumulation but large enough to supply a surface area able to receive the free piston 40 impact without permanent strain. The decoupled sleeve 38 travels up the separator rod body 1 to the portion with the smallest tolerance between the inner face and the separator rod body 1. At this point, the upper channel edge 7 may shear the residue accumulation on the inner face of the sleeve 38 as it travels to the sleeve stop 5. Once the sleeve 38 has reached the vertical limit of the sleeve stop 5, the passing gas current may be dispersed on the inner face of the sleeve 38. This gas dispersion in the tolerance of the inside of the sleeve 38 and separator rod body 1 may reduce friction. The passing gas current may also experience an influence in direction, giving the current direction a component perpendicular to the sleeve 38 inner face. A gas current with a direction component perpendicular to the sleeve 38 inner face may cause a drag force capable of rotating the sleeve 38 on the previously described low friction interface. This rotation may cause remaining residue accumulation and gas current carried residue to shear off on the lower channel edge 8. Clearance created by spherical channel may allow a passage for said residues to escape propelled by passing gas currents. Once the gas flow period ends and the sleeve 38 is allowed to descend back over the separator rod body 1, any remaining residue may be sheared off by contact with the lower channel edge 8. During the rotation, ascent and descent of the sleeve 38 the angle of contact between the inner face of the sleeve 38 and the upper channel edge 7, as well as the lower channel edge 8, is dependent upon the spherical angle 6. Optimization of the sleeve 38 rotation, residue shearing and gas dispersion may be adjusted with the amount of spherical angle 6. 

What is claimed is:
 1. A ball and sleeve separator rod comprising: a structure of a cylindrical bar; a set of one or more spherical and recessed channels.
 2. A ball and sleeve separator rod comprising: a structure of a diameter fluctuating cylindrical bar; a set of one or more spherical and recessed channels.
 3. A ball and sleeve plunger separator rod according to claim 1, wherein said rod further comprising: spherical channel(s) in addition to or without one or more channels parallel to rod length.
 4. A ball and sleeve plunger separator rod according to claim 1 further comprising: a structure tip that narrows by means of a linear bevel.
 5. A ball and sleeve plunger separator rod according to claim 1 further comprising: a structure tip that narrows by means of a convex bevel.
 6. A ball and sleeve plunger separator rod according to claim 1 further comprising: a structure tip that narrows by means of a concave bevel.
 7. A ball and sleeve plunger separator rod according to claim 1 further comprising: a set of one or more spherical channels indented into said rod with an alignment of constant angle.
 8. A ball and sleeve plunger separator rod according to claim 1 further comprising: a set of one or more spherical channels indented into said rod with an alignment of fluctuating angle.
 9. A ball and sleeve plunger separator rod according to claim 2, wherein said rod further comprising: spherical channel(s) in addition to or without one or more channels parallel to rod length.
 10. A ball and sleeve plunger separator rod according to claim 2 further comprising: a structure tip that narrows by means of a linear bevel.
 11. A ball and sleeve plunger separator rod according to claim 2 further comprising: a structure tip that narrows by means of a convex bevel.
 12. A ball and sleeve plunger separator rod according so claim 2 further comprising: a structure tip that narrows by means of a concave bevel.
 13. A ball and sleeve plunger separator rod according to claim 2 further comprising: a set of one or more spherical channels indented into said rod with an alignment of constant angle.
 14. A ball and sleeve plunger separator rod according to claims further comprising: a set of one or more spherical channels indented into said rod with an alignment of fluctuating angle. 